So you want to have the brake levers up top as well? You'll need inline levers for that which are different than the levers you currently have:
http://www.biketiresdirect.com/produ...tm_medium=base

Then you'll need a drop bar, new housing, cables and finally some brake levers. How do you shift now? Do you want to have an integrated lever and brake? If so then you might need to replace more than just the levers. I'd bring it by your LBS and get their opinion.